1. Field of the Invention
This invention relates to a coil bobbin used for an AC adapter converting alternate currents into direct currents.
2. Description of Related Art
Equipment to be used domestically such as a tape recorder, etc. can be operated by a dry batteries, and certain types of dry batteries are provided with an AC adapter as an accessory so that commercial power supplies may be used as a driving source.
FIG. 7 shows a certain example of circuits as being conventionally used for the above described AC adapter. This AC adapter circuit comprises a pair of input terminals T1 and T2. These input terminals T1 and T2 are configured in particular by a pair of AC blades.
The input terminals T1 and T2 are connected to a coil C1 on a primary side of a transformer T, and an alternating voltage is applied, and mutual induction action generates a predetermined alternating voltage at a coil C2 on a secondary side of the transformer T, and this alternating voltage is rectified from alternating current into direct current via a rectifying circuit configured by a bridge circuit of a diode 12 and a smoothing capacitor 13, etc. and converted into a predetermined direct voltage. This direct-current voltage is supplied to an electronic apparatus (not shown), such as a tape recorder, etc. via a detachable plug 28 having a known configuration.
An AC adapter, as shown in FIG. 8 is provided with, a coil bobbin 1' which is wound by the coils C1 and C2 and into which a core 9 is incorporated. One end side of this coil bobbin 1' is provided with an AC blade 10, and the other end side thereof is provided with a substrate 15. Electronic parts 14 such as a diode 12, and a smoothing capacitor 13, etc. are mounted on this substrate 15. These assembly bodies are accommodated in a case comprising a appropriately-shaped lower case 29, and a box-type upper case 30, etc.
Thus, in such a conventional AC adapter, the coil bobbin 1' is a type to be attached to the substrate, and has drawbacks that the electronic parts 14 cannot be directly incorporated into the coil bobbin 1', and that components are abundant in number.